The present invention relates to an internally ventilated disc brake having a brake disc, which consists of two friction rings, which are arranged spaced apart by means of ribs, between which are formed a plurality of air cooling channels, at least one heat dissipating element being arranged between the friction rings.
During the disc braking action heat is generated by the brake pads in the friction rings of the brake disc. This generated heat must be continuously dissipated for the operating safety of the disc brake. To fulfill this purpose, there are, for example, systems that include a heat dissipating element in a molding adapted to the shape of a cooling air channel and which later, after the manufacturing process of the brake disc, may be placed stationarily inside the cooling air channel. Such prior art systems are, however, very complicated and exhibit at most only a relatively unsatisfactory heat dissipating behavior.
An object of the invention is to provide an internally ventilated disc brake that enables an improved dissipation of heat from the brake disc with simultaneously a simpler and more economical design.
The foregoing objective has been achieved based on the recognition that at the existing rate of air flow the internal cooling of the brake disc may be increased, if the air contact surface of the cooling air channels is enlarged. The present invention solves this problem in that, during the manufacturing process of an internally ventilated disc brake, at least one heat dissipating element, that is to be cast or molded into the brake disc is assigned to a molding that forms the brake disc. The heat dissipating element is disposed, according to the present invention, in the parting plane or the center plane of the molding and is cast into the molding, at least in certain places. This provides that the heat generated by friction at the friction rings, is radiated or transferred to the heat dissipating element and from there can be carried away with the cooling air. The heat dissipating element may be advantageously disposed in the molding so that at the same time it projects, at least in certain places, into at least one cooling air channel of the brake disc. However, it is regarded as especially advantageous if the heat dissipating element is constructed or disposed in the molding such that, following the manufacturing process of the brake disc, the heat dissipating element projects into a plurality of cooling air channels or into all of the cooling air channels formed on the brake disc.
The early insertion or incorporation of the heat dissipating element into the molding, as early as during the casting operation or the manufacturing process of the brake disc, makes it possible to realize an especially simple and inexpensive and, thus, extremely effective configuration of a brake disc provided with a heat dissipating element. Thus, the manufacturing of the molding with an integrated heat dissipating element is carried out in a single molding process without having to finish the heat dissipating element itself at a later date. Arranging the heat dissipating element in the parting plane of the molding (this plane extending substantially parallel to the friction rings) has the advantage that the heat dissipating element in this position can develop very good efficiency, since, as a result, the air contact surface of the cooling air channels is very effectively enlarged.
The radial reach of the heat dissipating element may conform to the radial reach of the ribs and/or the radial reach of the cooling air channels. The specific configuration of the ribs and/or the cooling air channels themselves is unimportant to the scope of the invention because the heat dissipating element can be adapted in virtually any arbitrary way to the ribs and/or the cooling air channels. In this context the concept of a parting plane is defined as the parting plane of a mold for manufacturing the molding. This parting plane is advantageously at the same time the center plane of the molding. In manufacturing the molding, the heat dissipating element may be placed in this parting plane and held there during the manufacturing process.
The present invention provides that the heat dissipating element exhibits a cross section preferably in the shape of an annular ring and is constructed essentially as a disk-shaped and/or plate-shaped component. This guarantees an especially simple and, in addition, an especially optimal manufacturing process.
The heat dissipating element itself may be constructed as a single walled and/or a double walled component. A single wall configuration guarantees a very simple and inexpensive manufacture of the heat dissipating element, whereas the double wall configuration may exhibit an even better heat dissipation value.
Preferably, the heat dissipating element can exhibit material protrusions and/or outwardly curved sections of material in the area of the cooling air channels. The material protrusions and/or the outwardly curved sections of material may be made preferably by way of a punching, compression molding or embossing process. Thus, a plurality of material protrusions and/or outwardly curved sections of material may be provided quickly and simply on the heat dissipating element. It is also contemplated, however, to construct the material protrusions as separate components that may be, for example, subsequently welded, soldered and/or riveted on the outside of the heat dissipating element.
In this connection, the material protrusions are constructed preferably in a knob-like manner. The material protrusions can also be constructed in a cone-like or pin-like manner. In contrast, the outwardly curved sections of material may be constructed substantially in a web-like or tab-like manner. Compared to smooth components, the material protrusions and/or the outwardly curved sections of material make it possible to obtain a heat dissipation behavior and/or flow behavior that is improved a second time.
Furthermore, the heat dissipating element can be provided with cavities and/or perforations at least in the area of the ribs, provided on the friction rings, in order to guarantee a safe and reliable connection between the two friction rings. The cavities and/or perforations can be adapted advantageously in shape and number corresponding to the ribs provided on the friction rings.
An especially currently preferred embodiment is to make the heat dissipating element of sheet metal, in particular of aluminum, steel, copper or their alloys. A heat dissipating element that is made of sheet metal has a weight advantage, is economical to make and, in addition, is easy to process. The heat dissipating element should also especially preferably exhibit a higher heat coefficient than the friction ring, respectively the molding.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.